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Improvement of compatibility of liquid metals Li and Pb-17LI

ISLA2011. Improvement of compatibility of liquid metals Li and Pb-17LI Masatoshi KONDO, Minoru TAKAHASHI b) , Teruya TANAKA a) , Tsisar Valentyn c) and Takeo MUROGA a) Tokai university, Japan, a) National Institute for Fusion Science a) b) Tokyo Institute of Technology, Japan

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Improvement of compatibility of liquid metals Li and Pb-17LI

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  1. ISLA2011 Improvement of compatibility of liquid metals Li and Pb-17LI Masatoshi KONDO, Minoru TAKAHASHI b), Teruya TANAKAa), Tsisar Valentyn c) and Takeo MUROGA a) Tokai university, Japan, a)National Institute for Fusion Science a) b) Tokyo Institute of Technology, Japan c) Physico-Mechanical Institute of National Academy of Sciences of Ukraine, Ukraine

  2. Coating (MHD, Ttritum .etc) Er2O3 (DiP・MOCVD) Al2O3 Er2O3 (DiP・MOCVD) Nitride treatment Background -1 Fusion blanket IndiaTBM(2009) Pb-LI・solid breeder/RAFM Dr.Kumar et al FED KOREAHCML-TBM (2008)Li/RAFM Dr.KIM et al Japan (2003) molten salt Flibe/RAFM Dr.Sagara et al., FED Japan (2003) liquid metal Li/vanadium Dr.Muroga et al., FED Liquid breeder Structure Korea Lithium Li RAFM USA Europe India china Pure metal Japan Russia SiC Lead lithium Pb-17Li Alloy Vanadium alloy Japan Flibe LiF-BeF2 ODS Toward high temperature Molten salt

  3. 10µm Chemical composition (wt%) Background -2 (Structural material) Reduced activation ferritic martensitic steel is candidate structural material of blanket. Prior austenite grain boundary Block boundary Some sub grains Packet boundary Lath boundary Chemical reaction of steel’s base metal (Fe), alloying elements (Cr, W) and carbides with liquid metals Corrosion of RAFM steel in liquid metals

  4. Background -3 (Liquid breeders) Major characteristics of liquid breeders High thermal conductivity in liquid metal High chemical stability of molten salt Liquid Lithium Li+ Flinak Li+ F- + Free electron Already stable state by ion bonding

  5. Purpose Purpose of the present study is follows; • - Establish corrosion test technology for liquid Li and Pb-Li • Make clear the corrosion characteristics of RAFM JLF-1 steel in the liquid metals • Make clear the corrosion of coating in the liquid metals • Modeling of the corrosion of RAFM steel in the liquid metals

  6. Experimental procedure (1) Pb-17Li provided by santoku coop. Initial impurity of liquid metals (wppm) Experimental condition Carbon Li3N Li2O

  7. Experimental procedure (2) Static test (Simple immersion) Flowing test (Mixing vessel) Fixed specimen Influence of flow 3cc 48mm 100cc Width of impeller33m Rotation speed100 rpm Velocity around specimenv=πdn=0.17cm Re number for mixing

  8. Analysis of corroded specimen (a) Weight loss measurement (To estimate the corrosion (loss) rate) (b)SEM/EDX analysis for surface and cross section (To evaluate the metallurgical change of steels) (c) Impurity analysis of liquid breeders by ICP-MS( Fe, Cr, W, non metal impurity) (To investigate mass balance between loss in specimen and increase of metal impurity in melt ) Cleaning procedure for tested specimen Take out sample Immersion to ethanol Acetone Specimen in Li Li immersion at 350ºC Immersion to ethanol Acetone Specimen inPb-Li

  9. Experimental results (Mass loss of specimen by corrosion in Li) Weight loss of specimens (g/m2) Li (+0.5wt%Li3N) (Static) 250-hour Li (+0.8wt%Li2O) (Static) 750-hour Li (Pure) (Flow) 250-hour Li (+3.7wt%C) (Static) 250-hour Li (Pure) (Static) 250-hour - The influence of non-metal impurity (i.e. nitrogen and oxygen) in liquid Li was large on the corrosion loss. - The Influence of oxygen in Li on the corrosion was newly found.)

  10. Experimental results (Lithium) 20µm 20µm Li+0.5wt%Li3Nnitrogen dope (Cr dissplution) 選択的 10µm 10µm 10µm 10µm 20 hour 120 hour 250 hour Phase transformation Phase transformation C Fe c a a a a a BCC BCT 250 hour Initial Li+3.7wt%Ccarbon dope Li+0.8wt%Li2Ooxygen dope (Cr dissolution) No phase change Phase transformation 287 hour 122 hour 780 hour

  11. Li JLF-1 Thermal linear expansion % Er2O3 20µm Temperature (ºC) Corrosion of Er2O3 coating in Li Surface color was black after the corrosion test though the color was metallic luster before the test. Er concentration in Li unit: wppm (ICP-MS) 600ºC Er2O3/JLF-1 0 10 20 30 exposure(hour) Peeling off normal Crack Corroded (Er-Cr rich) SEM The oxide itself might be chemically stable in the liquid breeders. The damage was possibly made by a large difference of the thermal expansion ratio between adhered Li and the coating during a heat up and a cool down procedure of the corrosion test when the Li was solidified.

  12. Summery for corrosion in Li • Nitrogen dissolved in Li has big influence on the compatibility. It was newly found that oxygen in Li can increase the corrosion of steel. The nitrogen and oxygen dissolved as non-metal impurity in Li must be removed before the use. Carbon in Li can suppress the the depletion of carbon in the steel. • The issue for the coating of liquid blanket is the peeling of the coatings in the liquid metals.

  13. Experimental results (Weight loss of specimen in Pb-Li at static condition) Corrosion was suppressed when the metal element, i.e. Fe and Cr, in Pb-17Li was saturated..

  14. Experimental results (Pb-17Li) 600oC 750 hours 600oC 3000 hours Low mag. (x1000) Low mag. (x1000) 20µm 5µm 20µm 5µm High mag. (x3000) High mag. (x3000) The corrosion in JLF-1 was selective attack to some boundaries of microstructure.

  15. Experimental results (Corrosion of Er2O3 coating in Pb-Li) The oxide itself might be chemically stable in the Pb-Li. The damage of the coating was possibly made by a large difference of the thermal expansion ratio between adhered Pb-Li and the coating during a heat up and a cool down procedure of the corrosion test when the Pb-Li was solidified.

  16. 10µm 10µm Experimental results (Corrosion in flowing Li and Pb-Li) Flowing Li Flowing Pb-17Li Internal diffusion of liquid metals Erosion- corrosion was caused by peeling of subgrains after corrosion on surface. (FAC) (Erosion corrosion)

  17. Corrosion modeling Mass balance between increase of metal impurity in liquid breeders and corrosion ratio of specimen Transient of metal impurity in liquid breeders Corrosion ratio Concentration of metal in liquid breeders Mass loss of specimen by corrosion

  18. Mass transfer model in corrosion (Li) Different geometrical factor of corrosion system Volume / corrosion surface area Different corrosion device Large 600oC (Li) V/S Small

  19. Mass transfer model in corrosion (Pb- Li) 600oC (Pb-Li)

  20. Summery • Major conclusions are follows; • - Corrosion test technology for liquid Li and Pb-Li was established. • The corrosion characteristics of JLF-1 in static Li and Pb-Li were investigated. Then, we started to study about the corrosion in flowing condition. • Modeling of corrosion of JLF-1 in Li and Pb-Li was started. • Fundamental corrosion characteristics of anti corrosion coating in liquid Li and Pb-Li was studied. The issue is the peeling off of the coatings in liquid metals.

  21. 10µm Corrosion of Fe-Al coating in liquid Pb-Li SEM After 500- hour immersion in Pb-17Li at 600 degree C Coating it self was chemically stable in liquid Pb-Li. However, the peeling off is issues for the coating. Now, study on metal plating technology is under going. Fe-Al coating 316L Pb-Li 剥離 Pb O Fe Al

  22. Background -4 Corrosion phenomena At flowing static condition All liquid metals especially heavy liquid metal Liquid metal corrosion -Dissolution of steel element into liquid metals -Diffusion of metal elements of liquid metal into steel matrix At flowing condition FAC Erosion- corrosion GB attack Compatibility Determined by alloying process Determined by chemical potential of non-metal impurity Pb, Pb-Bi Li, Na, K, Pb-Li(?) Peering of corrosion products Formation of corrosion products (Carbides, oxides, nitrides, hydrides and so on) Solubility of metal elements and chemical potential of non- metal impurity in liquid metals are important parameters which determine the corrosion. 23

  23. Effect of nitrogen on corrosion in Li

  24. Experimental results (Transient of metal impurity in Pb-17Li) After the immersion of JLF-1 in Pb-Li. [1] M. G. Barker, P. Hubberstey, A. T. Dadd, S. A. Frankham, J. Nucl Mater., 114, 143-149 (1983). [2]V. Tsisar, M. Kondo, et al., J. Nucl. Mater, under review. H. U. Borgstedt, H. Feuerstein, J. Nucl. Mater., 191-194, 988-991. [3]N. Simon et al., Int. J. Heat Mass Transfer., vol.38, No.16, 3085-3090 (1995).

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